TiO₂/BiOCl heterojunction photocatalysts with different Ti/Bi weight ratios were synthesized by hydrothermal method and used for the photodegradation of norfloxacin (NOF). The as-prepared photocatalysts were characterized. The influences of temperature, catalyst dosage, initial NOF concentration and pH on the photodegradation performance were examined. Based on the results of HPLC-MS, intermediates and possible degradation pathways for NOF degradation were proposed. Based on TOC and 3D EEMs analysis, the mineralization ability of TiO₂/BiOCl composites on NOF molecules was investigated. Finally, the possible mechanism for the enhancement of photocatalytic activity of TiO₂/BiOCl photocatalyst was presented based on the density functional theory (DFT) calculations, experimental results of radical trapping and analysis of the charge transfer scheme under the internal electric field (IEF) formed in the heterostructure.